Measuring transducers are applied today in a wide variety of applications in industrial measurements technology. Pressure measuring transducers are produced and sold by Endress+Hauser under the mark CERABAR and pressure difference transducers under the mark DELTABAR.
Pressure and pressure difference transducers contain, respectively, pressure and pressure difference sensors for registering the pressure to be measured, or the pressure difference to be measured, and for transducing the same into an electrical variable. The sensors are usually equipped with sensor electronics, which conditions the electrical variable into a pressure dependent, electrical measurement signal. Measuring transducers are usually applied in measuring devices, which have measuring device electronics, to which the measurement signal is fed via an electrical connection from the measuring transducer to the measuring device electronics. However, pressure measuring devices are also known, in which energy supply of the pressure sensor and transmission of the measurement signal occur between measuring device electronics and pressure sensor electronics via a wireless connection. An example of an inductive coupling between a pressure sensor and measuring device electronics is described in DE 40 33 053 A1. The measuring device electronics determines the pressure to be measured based on the measurement signal and makes the measurement result available to a display, an additional application and/or for additional processing.
Modern electrical measuring devices and therewith also their measuring transducers must satisfy ever higher requirements for quality, safety and accuracy of measurement.
For this, most manufacturers have an active and comprehensive quality management for the manufacturing process. For quality assurance, especially, strict constraints are placed on the manufacturing processes, which require, especially, regular checking and exact documenting of the individual manufacturing steps. The identifiability of the measuring transducers and/or sensors plays an important role in this context. The identification of measuring transducers and/or sensors usually occurs based on labels applied thereon, via which the measuring transducers or their sensors are associated with serial numbers. The documenting of the manufacturing process is stored under the serial number, based on which, for example, manufacturing data, such as e.g. production data, batch numbers, etc., can then be ascertained.
However, labels or other forms of identifications or markings require space. A label typically has a size of 10 mm×10 mm. However, as miniaturization of electronic devices progresses, this space is not always present. Moreover, the labels of label-equipped components can become hidden during installation, so that then they are no longer readable.
The measuring transducer and/or their sensors are always subjected to ever more comprehensive calibration and/or test procedures, in order to fulfill the high requirements for safety and accuracy of measurement. These methods are now an inherent component of the manufacturing and are usually executed in corresponding production lineS, in which the measuring transducerS pass through correspondingly embodied production stations.
This means, however, a very high manufacturing effort, since each measuring transducer, for each of these procedures to which it must be subjected, must be mounted in the corresponding production station and, above all, in each case, must again be electrically connected. The electrical connection is required during this process to supply energy for the measuring transducer, especially its sensors, in order to be able to obtain their measurement signals.
In serial production, these procedures present a logistical problem to ensure that the results of the individual calibration, and/or test, methods are really associated with the measuring transducer from which they were derived.
A further problem is posed by those calibration and/or test procedures, in the case of which measuring transducer and/or sensor specific data must be recorded to be available for the faultless functioning of the measuring transducer and/or for achieving the desired accuracy of measurement in the measuring transducer and/or in a measuring device equipped with the measuring transducer. These include especially data derived from calibration procedures such as, e.g. characterizing parameters and/or curves, which are subsequently required for conditioning the measurement signal, for ascertaining pressure or pressure difference and/or for compensating measurement errors.
For example, sensor specific characteristic curves, which reflect the sensor specific response of the respective sensor as a function of the pressure, or pressure difference, acting thereon are recorded. Additionally, as a rule, a temperature dependence of the response is determined, which is subsequently used for the compensation of temperature dependent measurement errors of the pressure or pressure difference sensors.
There are pressure, or pressure difference, measuring transducers that include a pressure transfer means filled with a pressure transmitting liquid. The pressure transfer means serve to transfer to the sensor a pressure to be measured, for example, a pressure acting externally on an isolating diaphragm of the pressure transfer means. When pressure transfer means are used, then their response in terms of a transfer characteristic and the temperature dependence thereof must be taken into consideration. The temperature dependence can be derived, for example, using temperature sensors arranged in the pressure transfer means, as described, for example, in EP 0 764 839. In order to supply the temperature sensors with energy and to record their measurement signals, the temperature sensors arranged in the pressure transfer means must be electrically connected for these calibration and/or test procedures.
The data ascertained in the test and/or calibration procedures must, in each case, be correctly associated with the respective measuring transducer and/or sensor, buffered in the production station and forwarded to their ultimate destination. In such a case, the ultimate destination can also lie outside the measuring transducer. This is e.g. the case, when these data are required by the measuring device electronics of the measuring device, in which the measuring transducer is applied at a later point in time.
In DE 10 2006 024 743 A1, a measurement transmitter is described, which has a memory, in which calibration data and application or configuration data are stored, which in the case of a defective measurement transmitter can be read out via an external auxiliary device via an autarkic RFID interface and transmitted into the corresponding memory of a replacement device.